Fluoro substituted polysiloxanes and preparation thereof



UnitedStates Patent I l )over, N.J., assignors to Thiokol ChemicalCorporahon, Trenton, N.J'., acorporation of Delaware No Drawing.FiledMay 29, 1958, Ser. No. 738,620 6 Claims. (Cl. 260-4482) Thisinvention relatesto novel liquid polymers, in the form ofpolyorganofluorosiloxanes, and to methods of preparing them.

A principal object of this invention is to provide novelpolyorganofluorosiloxanes in the form of liquid polymers, which areuseful as hydraulic fluids, heat transfer media, instrument lubricants,and flotation fluids an gyroscopes and other instruments of this type.

Another principal object is to provide novel methods of preparing saidpolyorganofluorosiloxanes from one or more substituted silanes asprincipal. starting materials; these methods including hydrolyticpolymerization, cohydrolytic copolymerization, and catalyzedcondensation.

Another object is to provide'novel. polyorganofiuorosiloxanes whichpossess desirable densities, thermal stabilities, and viscosities.

Another object is to provide novel polyorganofluorosiloxanes which areor are not endblocked or chainstoppered, as desired. s

Other objects a nd advantages of this invention will appear as thedescription thereof proceeds.

The methods employed in determining physicaland chemical constants ofour novel polymers are described atth wi 1 a "ll't c t r w i ht,-A moleu ar ht mi tions were made by the cryoscopic method in benzene.

Viscosity.- Measurements of viscosity were made at various temperaturesup to 400 F. A Cannon-Manning semimicro viscometer was used in thesestudies. When the instrument was filled and placed in a bath maintainedat a predetermined temperature, approximately 8 minutes were allowed forthe liquid under test to come to thermal equilibrium. i

In the examples below viscosity values are given in centistokes (cs.). s

Viscosity index (V.I.).Viscosity indices were calculated from the*ASTMVisc'o'sity Tables (ASTM Special Technical Publicatien No; 43A,1953), in the usual manner.

.AlSTZl Islopes.- lhe data obtained in the viscosity tests r wereplotted on ASTM Standard Viscosity=Temperatu're Charts (ASTMdesignation: P341 343). ASTM'slop'es were taken directly from theviscosity-temperature curves so plotted.

Measurements ofdensity and of refractive iri dex were i made y ventionalmethods.

pr. aryl-dichlorofluorosilanes-eincluding methyldi Various fluorinatedsubstitution products of silane s5 amples :of it such fluorinatedstarting materials are (zi) fl ahama Apr. 25, 1961phenylmethylethoxyfluerosilane (C H CH SiOC H F).

We do not employ as a chief starting monomer a substituted silanecontaining more than one fluoro group on siliconffor our researches haveindicated that when more than one fiuoro group is attached to the samesilicon atom, all but one would be hydrolytically removed. The fluorogroup of a monofluorosilane is not readily removed? by hydrolysis. .Themondfluoro materials of groups (b)- and: (0): above consequently. mayact as end-blocking or chain-stopping reagents, as disclosed in ExamplesV, VI,

and XI below.

Another representative end-blocking or" chain-stopping reagent, which wehave employed in effecting polymerization of the foregoing fluorinatedstarting materials, is trimethyl'chlorosilane (.(CH SiCl) Methods ofpreparing certain of the foregoing fluorinated silanes, for use asmonomers or comonomers, and as chainterminating. agents, are describedand claimed in the pending application of Murray S. Cohen and JosephGreen, Serial No. 619,945, filed November 2, 1956, now U.S. Patent No.2,927,938.

We have prepared representative embodiments of our novelpolyorganofluo-rosiloxanes by the use of substantially differentmethods, including (a) hydrolytic poly merization, (b cohydrolyticcopolyrnerization, and (c)- condensation of: a silicon ester with anorganosilicon halide.

The first two of the foregoing methods may be carried out with thestarting materials in solution, as in benzene, or in the absence of sucha solvent; and an end-blocking agentmay or may not be involved.

Benzene as solvent.-Weighed quantities of starting materials, of theorder of.0.1 mole each, are dissolved in magnesiumsulfate.Afterfiltration the benzene solvent is distilled as, andother volatilesare removed by heating the residualoil to 240 to 280 C. for 10 minutesat a pressure of 5 mm. or less.

No solvent.A mixture of weighed quantities of starting materials isadded drop-by-drop, with vigorous stirring, to 100ml. of watercontaining 2 dropsof sulfuric acid. (He'reinafterthismixture of waterand sulfuric acid ordinarily will be designated asdilute sulfuric acid.)The acidulateiaqueous mixture is heated for 4 hours at to* C. The liquidreaction product is separated, and volatile materials are removed byheating at 240 to 245 C.-for aboutlQ minutes at 5 pressure or less. Theresidual liquid consists essentially of an organofiuoroil s ql mei-:-The use, in general, of the aforedescribed method of preparing apolyorganofluorosiloxane, employing benzene as a solvent, is illustratedin Examples I to V1, inclusive. Otherwise the respective disclosures inthese examples are i l d i9 f ct n da hat re p i u he o Example] (0.066mole) of trimethylchlorosilane. The residual polymer was a liquid,weighing 11.8 grams. Its prop erties, as measured, were:

Molecular weight 898 Viscosity (cs.) at:

32. F. 1966 77 F. 176 10o 1 t 91 210 F. l6 Viscosity index f I 146 ASTMslope 0.53

H We have assigned a formulate each of the organofluorosiloxane polymersdisclosed in our several examples. Bearing in'mind the general view thata synthetic poly mer is'not strictly a chemical individual, we believethat each of the new polymer formulas assigned by us presents withsufficient accuracy to those skilled in the calling the chemicalconstitution of the corresponding product. The essential bases for ourbelief just stated are (1) the known formulas of the several reactantsinvolved in the preparation of our novel polymers; and (2) the closeconformity of the calculated value to the observed value of themolecular weight of each polymer.

The formula for the polymer of Example I is CaHs(CH:):SiO(S|iO),Si(CHs)a where x represents the number of recurringunits. When x is taken as 5 in this formula, the calculated molecularweight of the polymer is 863.4, or 96.1 percent of the observed value of898.

Example II The reactants. dissolved in benzene, were 19.6 grams (0.1mole) of phenyldichlorofluorosilane and 5.4 grams (0.05 mole) oftrimethylchlorosilane. The residual liquid polymer weighed 12 grams.Observed data there- Except for the value assigned to x, the formula ofthis'polymer is the same as that in Example I. When x=7, its calculatedmolecular weight is 1143.8, or 102.5 percent of the observed value of1116.

1 Example III The reactants, dissolved in benzene, were 19.5 grams (0.1mole) of phenyldichlorofluorosilane, 10.8 grams (0.1 mole) oftrimethylchlorosilane, and 13.3 grams (0.1 mole) ofmethyldichlorofiuorosilane. The yield of residual liquid was 15.2 grams.Observed data thereon were:

Example IV A quantity of phenyldichlorofluorosilane-25.4 grams (0.13mole)-dissolved in benzene, was hydrolyzed in the absence of anyend-blocking or other molecular- Molecular weight 1051 Viscosity (cs.)at:

77 F. 55 F. j Y r 35 210 F. V 8.6 Viscosity index 168 ASTM slope I 0.52Refractive index .L 1.4620

The formula of this copolymer is I 2 Colin: CH:

(CHzbSiO(iiOfiiOhSKCHQi weight-controlling reagent. The product,consisting of 15.0 grams of a highly mobile liquid, did not yield anyvolatile fraction when heated at 240 to 257 C. for 10 minutes at 10 mm.pressure. Observed measurements thereon were:

Molecular weight 1300 Viscosity (cs.) at:

100 F. i 451 210 F. 44 Viscosity index ASTM slope 0.53

The formula of this polymer is When x=9, its calculated molecular weightis 1261.8, or 97.1 percent of the observed value of 1300.

Example V The reactants, dissolved in benzene, were 19.5 grams (0.1mole) of phenyldichlorofluorosilane, and 17.5 grams (0.1 mole) ofphenylmethylchlorofiuorosilane; the latter probably acting as amonofunctionalend-blocking agent. Observed measurements on the residualpolymer were: Molecular weight 894 Viscosity (cs.) at:

32 F. 688 100 F. 62.6 210 F. 10.7 400 F. 2.9 Viscosity index 143 ASTMslope 0.60 Refractive index 1.5222 Density 1.2437

The formula of this polymer is CH: CQHA CHI cflHssilo (SIiO) .s icm. F FF When x=4, its calculated molecular weight is 855.2, or 95.7 percent ofthe observed value of 894..

Example VI 7 The reactants, dissolved in benzene, were 164 grams (0.84mole) of phenyldichlorofiuorosilane and 97.8 grams (0.56 mole) ofphenylmethylchlorofiuorosilane; the latter, as in Example V, probablyacting as a-monofunctional end-blocking agent. Observed measurements ontheresidual polymer were:

'Except.ior thevalue assigned to x, the formula of this polymer is thesame as that in ExamplejVL (hel x-=3,

of the observed value 01 757.

its calculated, molecularjwei ght is 715, or 94.5percehts Example VIIThe reactantsin dilute sulfuric acid-were 6.7 grams (0.05 mole) ofmethyldichlorofluorosilane, 9.8 grams (0.05 mole) ofphenyldichlorofluorosilane, and 10.9 grams (0.1 mole) oftrimethylchlorosilane. The observed molecular weight of the product was1850; and its viscosity at 77 F. was 274 centistokes.

Except for the value assigned to x, the formula of this copolymer is thesame as that given in Example III. When x=8, its calculated molecularweight is 1908.8, or 103.2 percent of the observed value of 1850.

Example VIII The reactants-in dilute sulfuric acid-were 13.3 grams (0.1mole) of methyldichlorofluorosilane and 10.9 grams (0.1 mole) oftrimethylchlorosilane. The observed molecular weight of the product was1575. Its formula is When x=18, its calculated molecular weight is1568.2, or 99.5 percent of the observed value of 1575.

Example IX The reactants-in dilute sulfuric acid-and their respectivequantities were the same as those in Example VIII. A light yellow oil oflow viscosity was obtained. Its observed molecular weight was 1704. Itsformula, except for the value assigned to x, is the same as that inExample VIII. When x=20, its calculated molecular weight is 1724.4, or101.2 percent of the observed value of 1704. Example X The reactants-indilute sulfuric acid-were 19.5 grams (0.1 mole) ofphenyldichlorofluorosilane, and 10.9 grams (0.1 mole) oftrimethylchlorosilane. The observed molecular weight of the product was1060. Its viscosity (cs.) at 32 F. was 1966, and at 77 F. was 297. Its

Example I. When x=6, its calculated molecular weight is 1003.6, or 94.7percent of the observed value of 1060.

The formation of one of our novel polymers by condensing a silicon esterwith an organosilicon halide is illustrated in Example XI.

Example XI Ferric chloride (0.4 gram) was added to 24.5 grams (0.13mole) of phenylmethylfluoroethoxysilane and 16.5 grams (0.065 mole) ofdiphenyldichlorosilane. Ethyl chloride was evolved as the reactionmixture was heated slowly to 200 C. 'After cooling, the residue wasdissolved in benzene, and washed successively with water,

' formula, except for the value of x, is the same as thatin The formulaof this cop'olynier is ciH. GHs ira;

mos io s io SiCHs l (1511. x i

The observed molecular weight of 582 indicates that an almost equimolarmixture of products having X=l (M.W.=492) and X=2 (M.W.=690) wasproduced (M.W. of equimolar mixture=591). v

The aforestated objects of our invention are achieved by the variousnovel polymeric products disclosed in the foregoing examples; suchproducts being prepared by the methods described herein. Some of theuses of these polymers are as hydraulic fluids, heat transfer media,instrument lubricants, and flotation fluids for gyroscopes and otherinstruments of that type.

It is to be understood that modifications and changes in detail in theaforedescribed means and method steps may be made without departing fromthe spirit of our invention; and that all exemplifications and variantsof our novel methods and of the new products thereof, set forthhereinabove, are intended to be illustrative only, and in no senselimitative of the invention other than as the same is defined in theaccompanying claims.

We claim:

1. A low molecular weight liquid polyorganosiloxane polymer having arecurrent structural unit of the formula and chain terminating groups ofthe formula R R FSi, linked to the polymer chain by oxygen atoms,wherein R R and R are members of the class consisting of alkyl groupsand aryl groups.

2. A polymer as claimed in claim 1 in which R is methyl and R and R arerespectively phenyl and methyl. 3. A polymer as claimed in claim 1, inwhich R is phenyl and R and R are respectively phenyl and methyl.

4. A method of preparing liquid polyorganosiloxane polymers havingterminal fluoro groups which comprises condensing a monomer of theformula R FSiX in the presence of a chain terminating member of theformula .R R FSiY and ferric chloride as a catalyst, Where R R :and Rare members, of the class consisting of alkyl groups and aryl groups, Xis chlorine, and Y is an alkoxy group.

5; A method of preparing liquid polyorganosiloxane polymers havingterminal fluoro groups which comprises hydrolyzing a monomer of theformula in the presence of a chain terminating member of the formula R RFSiY wherein R R and R are members of the class consisting ofalkyl-groups and aryl groups, X is chlorine, and

with 1 percent aqueous sodium carbonate, and then with water. Thesolution was dried once over anhydrous magnesium sulfate. Afterfiltration, the solvent was distilled Y is a member of the classconsisting of chlorine and alkoxy groups. I

6. In the, methodof preparing a polyorganosiloxane,

the steps which comprise forming a mixture of weighed off, and theremaining volatiles were removed by heating to 240 C. at 6 mm. for 10minutes. The residual liquid weighed 20.6 grams. Observed measurementsthereon were: Molecular weight 582 Viscosity (cs.) atz I 1 77 F 91.4 100F 46.5 210 F 7.6 Viscosity index a a 130 Refractive index- 1.5493.Density 1 quantities of, (a) a monomer of the class consisting ofrnethyldichlorofluorosilane and .phenyldichlorofluorosil ane and (b) anend-blocking agent consisting ofphenyl methylchlorofluorosilane, addingsaid mixture drop-wise, with vigorous stirring, to dilute sulfuric acid,and heating the acidulated mixture for about 4 hours at to C.Referencesflited' in the file of thispatent UNITED STATES PATENTS(Other-references on following page) '7 UNITED STATES PATENTS GermanyMay 22, 1958 QTHER REFERENCES zvest ia Akad. Nauk SSSR, Otdel,

So'kolov et al.: I I

ages 806-811 (52 Chemical A b

1. A LOW MOLECULAR WEIGHT LIQUID POLYORGANOSILOXANE POLYMER HAVING ARECURRENT STRUCTURAL UNIT OF THE FORMULA